GJB2 and phenylketonuria: The autosomal recessive diseases reported with a carrier frequency higher than 1/40 were the following: GJB2-related DFNB1 non-syndromic hearing loss and deafness, cystic fibrosis, alpha-thalassemia, phenylketonuria, spinal muscular atrophy, familial Mediterranean fever, and autosomal recessive polycystic kidney disease (ARPKD) [31].